Polyamide and/or polyester textile reinforcements can be used as surface protection for drive belt surfaces, preferably at least their gripping or power-transmitting surfaces. Examples of such reinforcements include those based on aliphatic polyamides (for example, nylon) or polyesters as well as those based on aromatic polyamides (for example, aramide) or polyesters. Thus, such surface protection can, for example, be nylon fabric, polyester fabric or a fabric comprising a mixture of both nylon and polyester.
Addition polymers are polymers produced by polymer addition. The most important representatives are polyurethane and polyurea. Polyurethanes are produced by the addition of diisocyanates to polyalcohols, whereas for polyurea, diisocyanates are linked via addition reactions with polyamines.
Drive belts of the kind described above and methods for making them are disclosed in U.S. Pat. No. 6,419,775 and European patent publications 1,088,177 and 0,662,571. In these publications, toothed belts are described which have protective fabric on their teeth. The fabric is provided with a friction-reducing surface coating. The surface coating is a polymer matrix in which polytetrafluoroethylene is embedded. The polymer matrix is a bonding agent matrix of polyurethane, an addition polymer. According to U.S. Pat. No. 6,419,775, an abrasion-resistant composition which is available under the trademark XYLAN® from Whitford Plastics Limited is used as a surface coating. To form the coating, XYLAN® 1642-A-1429 is brought together with XYLAN® 1642-B-1452 and applied to the outer side of the toothed fabric. XYLAN® 1642-A-1429 is a mixture of short and medium chain diols and polyester-polyalcohols with short and medium carbon chains (1-6 C-Atoms) between the polyalcohol components with PTFE in an organic solvent and XYLAN® 1642-B-1452 is a hexamethylenediisocyanate-prepolymer with PTFE in an organic solvent. It has been shown that belts having the surface coating of XYLAN® are significantly improved with respect to wear protection and friction performance; however, these belts can fail prematurely because of tooth shearing when used in very high temperature ranges above 130° C.